[muawiyah]

Again, Carolina-guitano, as you note speciation was presumed to arise out of imperfect reproduction ~ that is, mutation. On the other hand, we now know that some species differ from others in but one gene, and by one "letter" transposed with another in the gene sequence.

So, what is it stokes the fires of speciation?

No doubt it's not that transposition by itself ~

[CarolinaGuitarman]

"Again, Carolina-guitano, as you note speciation was presumed to arise out of imperfect reproduction ~ that is, mutation."

Genetic variation + differential reproductive success.

"On the other hand, we now know that some species differ from others in but one gene, and by one "letter" transposed with another in the gene sequence."

Most differ by considerably more.

"So, what is it stokes the fires of speciation?"

Genetic variation + differential reproductive success.